NEW YORK (AP) — The makers of Butterball turkey, Twinkies and Wonder Bread have agreed to use less salt in some products as part of a national campaign against high blood pressure.

New York City health officials announced Tuesday that six more big food companies, including Butterball and Hostess, had joined an effort to cut salt levels in packaged foods by 25 percent over the next five years.

The city and other health departments and medical groups across the country are trying to persuade the nation’s food manufacturers to voluntarily use less salt. To date, 22 have signed on to the initiative.

Also joining Tuesday were pretzel and chips maker Snyder’s of Hanover, the sausage maker Premio, the tomato and bean packer Furmano’s and Delhaize America, which operates 1,600 East Coast supermarkets.

Everyone needs at least some salt, but most Americans consume double the recommended daily amount. Too much salt can lead to high blood pressure, which can be deadly.

By some estimates, cutting the nation’s salt intake by the initiative’s goal of 20 percent could prevent thousands of deaths each year.

Food manufacturers are traditionally wary about tinkering with tried-and-true recipes, and the initiative asks for subtle changes in product lines that could lose salt without a big effect on taste.

“It’s not even about products that taste salty … A lot of it is about hidden salt,” said Dr. Sonia Angell, director of the health department’s cardiovascular disease prevention program.

She noted that a muffin can have as much salt as a bag of potato chips.

“It’s very difficult to figure out which products have high salt without looking at the ingredients,” she said.

Butterball is cutting salt in deli meat and hot dogs.

Delhaize, which operates the Food Lion supermarket chain, is reducing salt levels in frozen pizza, cereal and butter. Premio is cutting salt in raw sausage. Snyder’s already meets the program’s target for its line of pretzels, but will now cut salt in some potato chips.